Reducing shrinkage of textile materials

ABSTRACT

A process for reducing the shrinkage of a textile material which comprises impregnating the textile with an aqueous dispersion of an aliphatic polyisocyanate and a polyglycol having a molecular weight between about 300 and 12,000 and a functionality based on hydroxyl groups between about 2 and 4 per molecule. The polyisocyanate and the polyglycol are reacted to render the textile less susceptible to shrinkage.

, nited States Patent 11 1 Carroll 1451 Nov. 12, 1974 I REDUCING SHRINKAGE ()F TEXTILE MATERIALS [75] Inventor: Clifford C. Carroll, Spartanburg,

[73] Assignee: Deering Milliken Research Corporation, Spartanburg, S.C.

22 Filed: Nov. 28, 1972 [211 App]. No.: 310,197

[52] [1.5. CI 8/127.6, 8/1155, 8/128 A, 117/1388 UA, 117/141 [51] Int. Cl. D06m 3/02, D06m 15/52 [58] Field Of Search 117/141, 138.8 UA; 8/127.6, 128 A [56] I References Cited UNITED STATES PATENTS 8/1972 Farmer.... 8/1276 1/1971 Habib ..8/l27.6

3.498740 3/1970 Cain 8/l27.6 2,537,064 I/l95l 2,893,898 7/1959 FOREIGN PATENTS OR APPLICATIONS l,097,5l6 l/l968 Great Britain Primary ExaminerHerbert B. Guynn Attorney, Agent, or FirmArthur L. Urban; H. William Petry [57] ABSTRACT 17 Claims, No Drawings REDUCING SHRINKAGE F TEXTILE MATERIALS This invention relates to a process for modifying the shrinkage characteristics of textile materials, and more particularly, relates to a process for reducing the relaxation and felting shrinkage of textiles.

The relaxation and felting shrinkages of textiles containing keratin fibers have been a serious problem in the textile industry. Various methods have been developed for inhibiting felting shrinkage such as digestion of the fiber scales by chlorination. Another method involves the use of acidand permanganate. Both of these methods are objectionable because of the loss of tensile strength and abrasion resistance which results from degradation of the fibers. Such processes also significantly increase the cost of a finished fabric since it is generally necessary to use higher weight starting materials to insure sufficient strength after degradation.

It also has been proposed to use various polymers or reactants to form polymers in the treatment of textiles for the purpose of reducing shrinkage. Polyamides, polyester and polyepoxides have been employed without significant success.

lsocyanates have been used in attempts to reduce the shrinkage of woolens. Although isocyanates alone have not been successful, combinations with polyols have been useful in the reduction of wool shrinkage. These processes achieve shrinkage reduction .without degradation and without creating unpleasant odors. One such process is described in US. Pat. No. 3,558,264. However, a problem in the stabilization of wool with isocyanates and polyols is the preferential reactivity of isocyanates with water. To eliminate this problem, the isocyanates and polyols have been employed in organic solvent systems or if aqueous systems are employed, the isocyanates have been blockedor in prepolymer form. Also, each of these expedients results in additional expense. With the organic solvents it is necessary to have a solvent recovery system. With blocked isocyanates and prepolymers, it is necessary to 'conduct these extra reaction steps which increase the cost.

In accordance with the novel process of the present invention, the disadvantages of prior processes are eliminated. The process of the invention provides a simple one-step aqueous impregnation of a textile with monomeric materials. Moreover, the process of the invention provides an improved textile material with re-' duced shrinkage characteristics which is free of yellowing tendencies. The invention also provides a novel process for stabilizing synthetic textile materials against shrinkage problems encountered during their production, e.g., during drying.

The process of the invention for reducing shrinkage of a textile material comprises impregnating the textile with an aqueous dispersion of an aliphatic polyisocyanate and a polyglycol and reacting these materials to render the textile less susceptible to shrinkage. The polyglycol has a molecular weight between about 300 and 12,000 and a functionality based on hydroxyl groups between about 2 and 4 per molecule.

Advantageously the textile material contains keratin fibers although the benefits of the invention also are achieved when synthetic, wool-like fibers, for example, acrylic fibers are used. While such synthetic fibers do not possess the shrinkage and felting characteristics encountered with wool and other keratin :fibers, some of these fibers have shrinkage characteristics at the very high temperatures often encountered during drying cy cles.

The aliphatic polyisocyanates employed in the process of the invention may have saturated or unsaturated aliphatic chains. Advantageously the aliphatic portions of the molecules are cycloaliphatic and preferably polycycloaliphatic. Examples of suitable polyisocyanates include dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, and the corresponding diisothiocyanates. Additional isocyanates include alkylene diisocyanates and diisothiocyanates such as propylene-1,2 diisocyanate, buty1ene-l,2 diisocyanate, butylene-l,3 diisothiocyanate and butylene- 1,3 diisocyanate; alkylidene diisocyanates and diisothiocyanates such as ethylidene diisocyanate CH Cl-I(NCO) and heptylidene diisothiocyanate CH (CH CH(CNS) In addition, mixtures of the various isocyanate compounds may be employed.

The polyglycol employed for reaction with polyisocyanate as pointed out above has between 2 and 4 hydroxyl groups per molecule with the higher number of hydroxyl groups being preferred. The molecular weight of the polyglycol is in the range of about 300 to 12,000 and preferably between about 3,000 and 6,000. The polyoxyalkylene portion of the polyglycol can be varied over a wide range, e.g., about 5 percent to percent of the polyol weight and preferably about 10' percent to 30 percent. Suitable polyglycols include mixed glycols,

that is, mixtures of different glycols or one glycol containing more than one type of polyoxyalkylene chain.

Especially useful are polyglycols in which the polyoxyalkylene chains include both polyoxyethylene and polyoxypropylene molecules. The triols may be formed by the addition of polyoxyalkylene chains to trifunctional compounds such as glycerol, hexanetriol, triisopropanolamine and the like. Suitable tetrols have four polyoxyalkylene chains attached to a tetravalent compound such as pentaerythritol or a diamine, e.g., ethylenediamine. Sulfur analogs of the above compounds also may be employed.

As pointed out above, the polyisocyanate and polyglycol are applied to the textile material as an aqueous dispersion and preferably in emulsion form. Generally, an emulsifying agent is included. Examples of suitable emulsifying agents are the sodium salt of lauryl alcohol sulfate, dioctyl sodium sulfosuccinate, sodium salts of alkylaromatic sulfon'ic acids, ethoxylated nonylphenol, and alkyl aryl polyethylene glycol ether. It may be desirable to include in the emulsion a small amount of an organic liquid which does not react with the polyisocyanate. Organic liquids such as benzene, toluene, xylene, chlorinated hydrocarbons, e.g., carbon tetrachloride, and trichloroethylene, aid in the preparation of the emulsion and penetration of the chemicals intothe structure of the textile. The emulsifying agent and any solvent are employed in minor amounts, e.g., from 0.1 percent or 0.2 percent up to about 10 percent or so.

The textile material which is treated in accordance with the invention may be in the form of yarns, threads or preferably a fabric. The fabric may be woven, knitted or nonwoven in form. The pH of the fabric undergoing treatment is important with extremes of pH either acidic or basic being undesirable. Preferably, the

pH of the fabric is between about 4 and 9; that is, a'

water extract of the fabric is in the 4 to 9 pH range.

To catalyze the reaction of the polyisocyanate and polyglycol it is advantageous to include a catalyst in the aqueous dispersion. Useful catalysts are organo metallic compounds, e.g., zinc naphthenate, and preferably organo tin compounds including dibutyl tin dilaurate, dibutyl tin diacetate, dilauryl tin diacetate, dibutyl tin maleate, dioctyltin dichloride, tributyl tin chloride and butyl tin triacetate. Amino compounds may be used as catalysts so that for example, when polyglycols based on diamines are used, an additional catalyst may not be necessary.

The proportion of the polyisocyanate in the aqueous dispersion should be sufficient to provide an excess over the polyglycol on an equivalent basis. Advantageously, the ratio of isocyanate groups to hydroxyl groups may be as great as about 4:1, with ratios between about 2:1 and 3:1 being preferred. Such ratios provide a substantial improvement in shrinkage characteristics without rendering the textiles excessively stiff and boardy.

The dispersion may be applied to the textile by any suitable means such as spraying, dipping and preferably padding. After the chemicals have been applied to the textile, excess liquid is removed allowing about 60 percent to 100 percent liquid based on the weight of the textile to be retained. Thereafter, the textile is dried, preferably at an elevated temperature, e.g., a temperature between about 220 and 325 F. With textiles con taining wool, a temperature between about 260 and 290 F. is desirable.

The proportion of polymer (the total of isocyanate and polyglycol) to provide satisfactory inhibition generally is in the range of about 0.5 percent to percent advantages in that the above improvements in textile characteristics are achieved by a simple one-step aque ous impregnation process with monomeric materials.

The invention will be described in greater detail with reference to the following examples which are intended to illustrate the invention without restricting the scope thereof.

EXAMPLE I A series of aqueous emulsions are prepared in the proportions listed in Table I. The dicyclohexylmethane diisocyanate is dissolved in an equal weight of toluene and the solution mixed with a mixed polyoxyethylenepolyoxypropylene tetrol (molecular weight about 4,000 and about 20 percent oxyethylene) available from BASF Wyandotte Corp. as Tetronic 702, sodium lauryl sulfate, dibutyl tin dilaurate catalyst and water. Each of the emulsions is applied to a woolen fabric and squeezed to a 100 percent wet pickup. The treated fabric is dried at 275 F., collected in a roll and stored for 72 hours at room temperature. Swatches of the respective fabrics are washed in a Sears Kenmore washer, normal cycle, using 105 F. wash water and two Salvo detergent tablets. The fabrics are then tumble dried in a Kenmore Dryer at the wash and wear setting for 20 minutes. The cycle is repeated five times after which the shrinkages are measured. The proportions of various ingredients and the shrinkages are listed in Table I below together with the shrinkage measurements of an untreated fabric.

It is apparent from the above measurements that fabrics treated in accordance with the method of the invention have much less shrinkage both in the warp and filling direction than the untreated control.

TABLE 1 Untreated Sample No. 1 2 3 4 Control Polymer 2.8 4.3 5.7 7.2 Dicyclohexylmethane 0.7% 1.1% 1.4% 1.8%

Diisocyanate Toluene 0.7% 1.1% 1.4% 1.8% Tetronic 702 2.1% 3 2% 4.3% 5.4% Sodium Lauryl Sulfate 0.2% 0.2% 0.2% 0.2% Dibutyl Tin Dilaurate 0.01% 0.01% 0.01% 0.01% Ma i 2) Five Washes/Dries Warp 5.8 3.8 3.0 2.4 21.2 Fill 3.5 2.7 2.4 1.6 8.4

on the weight of the textile material and particularly EXAMPLE ll between about 2 percent and 6 percent.

After the drying step, it is desirable to allow the fabric to age prior to further processing. This ageing is believed to be a continuation of the reaction mechanism. The ageing may be conducted for any desired period of time based upon the degree of shrinkage improvement desired, with a minimum of about 24 hours providing a substantial reduction in shrinkage characteristics. The ageing period may continue for a number of days up to five or more but generally an ageing period of about 3 days provides good results for most textile materials.

Stabilized textiles are achieved according to the pro-.

A series of aqueous emulsions are prepared in the proportions listed in Table II. The dicyclohexylmethane diisocyanate is dissolved in an equal weight of toluene and the solution combined with Tetronic 702, sodium lauryl sulfate, dibutyl tin dilaurate, softener and water. Each of the formulations is padded onto a percent acrylic double knit fabric and squeezed to provide a 100 percent wet pickup. The treated fabrics are dried at 325 F. for 4 minutes, collected on a roll and stored at room temperature for 48 hours.

The fabrics are washed in the Kenmore washer of Example 1 using F. water containing 0.1 percent on the weight of the fabric of Dupanol WAQE surfactant and dried at 275 F. for 3 /2 minutes at original dimensions. The fabric samples are then washed in the Kenmore washer of Example 1 using /2 cup of Tide detergent and F. water followed by tumble drying in a Kenmore Dryer for 20 minutes at the wash and wear.

setting. The shrinkage measurements after 1, 5 and 10 washes are set forth in Table 11 together with that of an The dyed fabrics are measured for dimensional untreated fabric. In addition to the improved shrinkchanges with the results set forth in Table III. A visual age, the crease resistance and flat appearance of the comparison of the treated fabrics and the untreated treated fabrics are superior to that of the untreated control shows that the treated fabrics have better hand,

control fabric. 5 yarn definition and general appearance.

TABLE II Untreated Sample No. 5 6 7 8 Control Dicyclohexylmethane 1.0% 1.4% 2.2% 2.2%

Diisocyanate Tetronic 702 2.6% 3.6% 3.6% 5.8% Toluene 1.0% 1.4% 2.2% 2.2% Sodium Lauryl Sulfate 0.2% 0.2% 0.2% 0.2%. Dibutyl Tin Dilaurate 0.05% 0.05% 0.05% 0.05% Softener 0.3% 0.4% 0.4% 0.6% Shrinkage 1%) One Wash/Dry Warp 2.6 1.7 2.0 2.8 5.3 Fill 0.4 1.1 0.8 0.7 0.0 Five Washes/Dries Warp 2.8 2.0 2.9 2.7 7.1 F' 0.4 1.5 0.8 0.7 0.0 Ten Washes/Dries Warp 3.7 2.2 3.0 3.0 7.6 Fill 0.4 1.0 0.0 1.0 0.5

T TABLE III Untreated Sample No. 9 1O 11 Control Dicyclohexylmethane 1.1% 1.7% 2.5% Diisocyanate Tetronic 504 2.9% 4.3% 5.8% Toluene 1.6% 2.4% 3.2% Sodium Lauryl Sulfate 0.12% 0.18% 0.2% Shrinkage Warp 1.3 2.0 2.0 7.0 Fill 6.0 5.3 6.0 22.0

Y EXAMPLE Ill EXAMPLE IV I A double knit acrylic fabric similar to that of Exam- A series of aqueous emulsions are prepared utilizing I ple III is treated with the aqueous emulsion as set forth the proportions listed in Table III. Tetronic 504 is a tetbelow to provide a 125 percent wet pickup and 5 perrol similar to that employed in Examples 1 and II but 40 cent polymer on the fabric. The fabric is dried at 225 having a molecular weight of about 3,400 and about 40 F., collected in a roll and allowed to age for 72 hours. percent oxy thylene cont nt. a h of th ulsi s is The treated fabric together with'ahuntr'atdcciiirfi applied to a 100 percent double knit acrylic fabric and sample is dyed in a Beck dyeing machine at atmosqueezed to provide 100 percent wet pickup. The spheric pressure using the dyestuff of Example III. The treated fabric is dried-at 220 F. for 4 minutes, coltemperature of the bath is raised to boiling in about 1 lected in a roll and stored for 72 hours at room temperh r a d th mai tained at the boil for 1 hour addiature. Prior to dyeing, the abrics re m ed a 0 n tional. A softener is added to the fabric in the dye maintervals both in the warp and filling direction and then chine by exhaustion. The dyed fabric is wet with water, dyed together with an untreated control fabric in a squeezed to remove excess liquid and dried at 275 F.

Beck dyeing machine at atmospheric pressure using 2 The fabrics treated in accordance with the invention percent on the weight of the fabric Sevron Blu 6- vhave a crisp firm hand as compared with an untreated The fabric is held at the boil for minutes and then and dyed fabric which has a soft mushy hand.

slowly cooled to F. 0.75 percent on .the weight of The fabrics are washed and dried l, 5 and 10 times fabric Sapamine WL softener sold by CIBA is exhaustaccording to the procedure of Example I. The shrinkedly applied to, the fabric from the dye bath. The fabric 55 age measurements of the Examples are reported-in 1S dried without tension. Table IV.

TABLE IV Dicyclohexyl Diisocyanate 4 1.12% Tetronic 504 2.81% Sodium Lauryl Sulfate I 0.50% Dibutyl Tin Dilaurate 0.005%

Shrinkage Sample No. 12 One Wash/Dry Five Washes/Dry Ten Washes/Dry Treated and Piece Dyed v Warp 2.0 4.0 5.0 Fill 2.0 1.0 0.5 Untreated and Piece Dyed Control Warp -l.5 -l.0 3.0 6.5

Fill 1 1.0 10.0

EXAMPLE v Blend fabrics (85 percent wool/15 percent nylon) bonded to nylon tricot and also unbonded plain fabric are padded with the aqueous emulsions set forth in Table V to obtain 70 percent wet pickup and 3.85 percent polymer on the bonded fabric and 80 percent wet pickup with 4.4 percent polymer on the unbonded fab- Hunter jet dyeing machine. The dyed fabrics are finished according to conventional wool fabric finishing procedures. The fabrics are steamed for 20 seconds, vacuumed for 10 seconds and dried. The fabrics are washed according to the procedure of Example 1 and air dried. The shrinkage measurements on the fabrics and the pilling resistance test results are reportedin Table VI.

TABLE VI Sample No, l5 l6 Treated, Untreated, Treated, Untreated, Beck Dyed Beck Dyed Jet Dyed Jet Dyed Control Control Steam Shrinkage 2.4 6.6 2.7 5.6 Warp 3.0 3.6 2.5 2.5

Fill Net Shrinkage One Wash/Screen Dry Warp 2.0 12.8 1.9 13.3 Fill 1.8 4.8 1.7 5.2 Five Washes/Screen Dry Wa 2.9 26.4 3.2 23.9 Fill 2.2 13.7 2.3 12.3 Ten Washes/Screen Dry Warp 3.0 29.7 3.8 27.7 Fill 3.3 18.2 2.6 17.5

PlLLlNG TEST Sample No. 15 16 Treated, Untreated, Treated, Untreated, Beck Dyed Beck Dyed Jet Dyed Jet Dyed Control Control lnitial 5.0 4.0 5.0 4.0 After Five Washes and Screen Dry 5.0 1.0 5.0 1.0

ric. The fabrics are dried at 275 F., collected on a roll and aged for 72 hours. After ageing, the fabrics are sheared and semi-decated according to conventional wool finishing procedures. The shrinkage and pilling resistance of the treated fabrics and untreated controls are set forth in Table V, with the pilling resistance rating being based on a 1 5 scale with a 5 rating best.

That which is claimed is: 1. A process for reducing the shrinkage of a woolen or polyacrylic fiber-containing textile material which 35 comprises impregnating said textile with an aqueous dispersion of a cycloaliphatic polyisocyanate and a polyglycol having a molecular weight between about 300 and 12,000 and having four hydroxyl groups per TABLE V Dicyclohexylmethane Diisocyanate 1.4% Trichloroethylene 1.4 Tetronic 702 4.1 Sodium Lauryl Sulfate 0.4 Dibutyl Tin Dilaurate 0.02

Shrinkage Sample No. 13 14 Unbonded, Unbonded, Bonded, Bonded,

Treated Untreated Treated Untreated Control Control Steam Shrinkage Warp 0.7 5.0 1.3 4.5 Fill 0.8 1.7 1.4 1.8 Net Shrinkage 5 Washes/Screen Dry Warp 2.2 20.2 2.7 16.4

Fill 1.8 11.1 1.1 9.9 Net Shrinkage 10 Washes/Screen Dry Warp 2.7 23.0 3.1 20.3 Fill 2.2 14.6 2.4 13.7 Pilling Resistance Initial 5.0 4.5 5.0 4.3 5 Washes 5.0 3.3 5.0 3.1

EXAMPLE VI molecule and four polyoxyalkylene chains including A 100 percent woven woolen fabric is treated with the emulsion of Example V to provide 75 percent wet pickup and 4.1 percent polymer on the fabric. The fabric is dried at 275 F., collected on" a roll and stored for 72 hours. The fabric is divided in half. One-half is dyed in an atmospheric Beck dyeing machine, the other in a both polyoxyethylene and polyoxypropylene molecules, reacting said polyisocyanate and said polyglycol 65 to render said textile less susceptible to shrinkage and drying said textile, the ratio of isocyanate groups in the polyisocyanate to hydroxyl groups in the polyglycol being between about 2:1 and 3:1.

2. The process according to claim 1 wherein the polyisocyanate is a polycycloaliphatic polyisocyanate.

3. The process according to claim 1 wherein the polyglycol has a molecular weight between about 3,000 and 6,000.

4. The process according to claim 1 wherein the reaction is conducted in the presence of a catalyst.

5. The process according to claim 4 wherein the catalyst is an organo metallic compound.

6. The process according to claim 5 wherein the catalyst is an organo tin compound.

11. The process according to claim 1 wherein the fabric contains acrylic fibers.

12. The process according to claim 1 wherein the fabric is dried at an elevated temperature.

13. The process according to claim 1 wherein the fabric is dried at a temperature between about 220 and 325 F.

14. The process according to claim 1 wherein the fabric after drying is stored in roll form for at least 24 hours.

15. The process according to claim 1 wherein the fabric after drying is stored in roll form between about 24 and 120 hours.

16. A textile material produced according to the cess of claim 1.

17. A textile fabric produced according to the process of claim 1 in which between about 0.5 percent and percent polymer is present in the fabric.

pro- 

1. A PROCESS FOR REDUCING THE SHRINKAGE OF A WOOLEN OR POLYACRYLIC FIBER-CONTAINING TEXTILE MATERIAL WHICH COMPRISES IMPREGNATING SAID TEXTILE WITH AN AQUEOUS DISPERSION OF A CYCLOALIPHATIC POLYISOCYANATE AND A POLYGLYCOL HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 300 AND 12,000 AND HAVING FOUR HYDROXYL GROUPS PER MOLECULE AND FOUR POLYOXYALKYLENE CHAINS INCLUDING BOTH POLYOXYETHYLENE AND POLYOXYPROPYLENE MOLECULES, REACTING SAID POLYISOCYANATE AND SAID POLYGLYCOL TO RENDER SAID TEXTILE LESS SUSCEPTIBLE TO SHRINKAGE AND DRYING SAOD TEXTILE, THE RAIO OF ISOCYANATE GROUPS IN THE POLYSIOCYANATE TO HYDROXYL GROUPS IN THE POLYGLYCOL BEING BETWEEN ABOUT 2:1 AND 3:1.
 2. The process according to claim 1 wherein the polyisocyanate is a polycycloaliphatic polyisocyanate.
 3. The process according to claim 1 wherein the polyglycol has a molecular weight between about 3,000 and 6,000.
 4. The process according to claim 1 wherein the reaction is conducted in the presence of a catalyst.
 5. The process according to claim 4 wherein the catalyst is an organo metallic compound.
 6. The process according to claim 5 wherein the catalyst is an organo tin compound.
 7. The process according to claim 1 wherein the dispersion is an aqueous emulsion.
 8. The process according to claim 7 wherein the emulsion includes an emulsifying agent or an organic liquid.
 9. The process according to claim 8 wherein the aqueous emulsion has a pH between about 4 and
 9. 10. The process according to claim 1 wherein the fabric contains keratin fibers.
 11. The process according to claim 1 wherein the fabric contains acrylic fibers.
 12. The process according to claim 1 wherein the fabric is dried at an elevated temperature.
 13. The process according to claim 1 wherein the fabric is dried at a temperature between about 220* and 325* F.
 14. The process according to claim 1 wherein the fabric after drying is stored in roll form for at least 24 hours.
 15. The process according to claim 1 wherein the fabric after drying is stored in roll form between about 24 and 120 hours.
 16. A textile material produced according to the process of claim
 1. 17. A textile fabric produced according to the process of claim 1 in which between about 0.5 percent and 20 percent polymer is present in the fabric. 